Drawing table



ca. E. FROELICH DRAWING TABLE April 24, 1934.

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G. E. FROELICH DRAWING TABLE Filed April 6. 1931 4 Sheets-Sheet 4'IIIIIIIIIIIIIIIIIII I u 1 I I I u I Patented Apr. 24, 1934 UNITED STATESPATENT OFFICE 1,956,546 DRAWING mam George E. Froelich, Two Rivers,Wis., assignor to Hamilton Manufacturing Company, Two Rivers, Wis., acorporation of Wisconsin Application April 6, 1931, Serial No. 527,887

6 Claims. (Cl. 45-131) This invention like, and, among combined drawingboard and desk which may berelates to drawing tables or the otherobjects, aims to provide a used simultaneously.

The drawing board is pivoted to the desk so as to be spaced therefromand is easily and readily adjustable to any desired angular relationshipwith the desk or base.

My improved construction permits the drawing board to be used in avertical position, as well as in a horizontal position, or variations.therebetween, and is desirably inclusive of simultaneously operablemechanism for securing the parts in said relative adjustment.

My invention may be understood and other objects will be apparent byreference to the illustrative embodiment shown in the accompanyingdrawings, in which- Figure 1 is a perspective view of a combined drawingboard and desk embodying my invention;

Figure 2 is a side elevation showing the associated mechanism, with thedrawing board and desk partially in Figure 3 is a partial plan sectiontaken on the section line 3-3 of Figure 2 and showing one end of thedesk;

Figure 4 is another partial plan section taken on the line 4-4 of Figure2 and showing the other end of the desk;

Figure 7 is a 7--7 of Figure 8;

plan section taken on the line Figure 8 is a fragmentary side elevationtaken as an enlarged reverse view of Figure 2; and

Figure 9 is a section taken on the line 9-9 of Figure 8 and showing theclutch contact.

Referring in detail to the drawings, I have shown, in general, a base,such as the desk 1, constructed preferably of metal, and a drawing board2 pivotally mounted thereon. The desk 1 has, in its front, drawers orthe like as indicated at 3 and a knee aperture such as 4. The drawingboard ample, thus saving floor space. To facilitate such use the drawingboard is arranged to be spaced rrom the-top of the desk.

At each end of the desk may conveniently be left compartments generallyshown at 5 and 6 in which may be housed mechanism for adjusting theposition of the drawing board. r

In the illustrative construction, I have shown, within each compartmentat each end of the desk 0 and hinged thereto by means of pivots '1 and8, two links 9 and 10. The pivot 8 may be upon a rod 8a which extendsfrom one of the compartments to the other, thus desirably reinforcingthe structure (Figures 3 and 5). Slots 1a in the com- 5 partments 5, 6,permit the links 9, 10 to' project therefrom. a

The free ends or the lings 9, 10 are hingedly connected together by astrut 11 so'that the links 9, 10 can be swung parallel to each other onthe pivots '7, 8. The strut 11, which carries a pivot 11a for thedrawing board 2, is thus movable ups wardly or downwardly and may belocked in any? desired vertical position within the range of its"movement, by means or a friction clutch mechanism associated with one ormore of the links.

As best seen in Figures 1, 3 and 4,'there may be two sets of links 9 and10, and associated mechanism, one set being located at each end of thedesk and each set being the substantial duplicate of the other but inreversed complementary arrangement. By means of such mechanism, theangular relation of the links to the base may be adjusted at will. 7

Referring in particular to Figure 2, which shows compartment 5 and itsenclosed mechanism, at one end of the desk, I- have shown the link 9enlarged in the region of its pivot point to form a cylindrical brakedrum 12. Located within the brake drum 12-and arranged to havefrictional engagement with the inner periphery thereof, is a generallycircular metal brake band 13. At the upper side of the drum 12, thebrake band 13 is supported by a pin 14 carried bya bracket 15 which maybe screwed to a carrier plate 18 appropriately mounted upon the wall ofthe compartment 5. The brake band 13 has some inherent flexibility andmay have its flexibility enhanced as for example by being partiallysplit at 17. The brake band is fully split at 18 and is normally heldexpanded to have frictional engagement with the drum 12, by means hererepresented asan elliptical cam 19 which is pivoted upon a'bracket 20also attached to the carrier plate 16 and which also assists inmaintaining the brake band in position in the drum 12. The cam 19 beinglonger in one direction than time other is thus adapted, by beingrotated in one direction on its horizontal axis, to press the brake bandagainst the drum 12 and thus to prevent the drum from rotating. This inturn, prevents movement of the links 9 and 10 and the connecting strut11 and holds the strut 11 in a given vertical position. The cam 19 isnormally held in such locked position by the tension of a coil spring20a, appropriately anchored at one end to a fixed portion of the deskand having its free end hooked to an arm 21 which is rigidly connectedto the cam 19 and is adapted-to rotate the cam. The tension of thespring 20a may conveniently be adjusted by a screw bolt 22 at itsanchored end.

When it is desired to move the strut 11 to vary the vertical position ofthe pivot 11a of the board 2, the above described clutch mechanism maybe released, preferably by a pedal which controls the clutch mechanismsat both ends of the desk simultaneously. I have here shown the pedal 23conveniently located for operation by the foot of the draftsman, forexample and mounted upon a forked lever 24 extending to each end of thedesk. One fork of the lever 24 is pivoted, for example, upon a bracket25 screwed to the carrier plate 16 and is continued beyond this pivot tobe hingedly secured to one end of a link 26. The other end of the link26 is hingedly secured to the arm 21, which, as before described, isrigidly connected to and is in rotatable relation with,

the cam 19. When the pedal 23 is depressed, the cam 19 is thus rotated,against the tension of the spring 20a. and in a reverse direction, aslight but sufficient distance to release the pressure of the cam uponthe free ends of the brake band 13, and permit rotation of the drum 12and, in turn, movement of the links 9, 10 and strut 11. Relatively lightcoil springs 27, hooked across the segments of the brake band 13,supplement the resiliency of the band to effect its contraction awayfrom the drum 12 to the extent permitted by the cam 19.

When the pedal 23 is depressed, in order that the drawing board 2 shallbe prevented from dropping and may be raised, for instance, with aslight pressure of the hand, I provide means for counterbalancing thedrawing board and its associated mechanism. In the presentexemplification of the invention, I have'shown the drum 12 extended uponits side opposite the strut 11 to provide an integral arm 28 to which ishooked the free end of a relatively heavy coil spring 29. The arm 28 isdesirably about as long as the link 9 to enhance the eifectiveness ofthe spring 29 by relatively long lever arm action. The spring 29 isanchored at its other end to a stationary part of the desk 1, and whenthe brake is released, the tension of the spring 29 is such as tocounterbalance the weight of the drawing board and its associatedmechanism and maintain the parts in equilibrium. It will be understood,as already explained, that, as here shown, there are two of the springs29, one at each end of the desk. If desired the tension of the spring 29may be such as to have a tendency to move the board 2 slowly upward whenthe clutch mechanism is released.

In order to adjust not only the angular rela tion of the links 9 and 10to the desk 1, (and thus the height of the strut 11) but also theangnlarrelation of the board 2 to the strut 11, I provide means for pivotingthe drawing board to the strut and clutch mechanism associatedtherewith, for maintaining a given angular relationship therebetween.

In this instance, the board 2 is rigidly mounted upon a frame 30 whichis pivoted to the strut 11 at 11a. The top of the strut 11 is shownhaving an integral enlargement which forms a cylindrical drum 31concentric with the pivot 11a, and about which the frame 30 (with theboard 2 thereon) may have an orbital or rotative movement.

'It will be here necessary to describe only one of the sets of mechanismassociated with the drum 31, it being understood that there may be, ashere shown, a. set at each end of the board, one set being a duplicateof the other but in reverse, complementary position.

As best shown in Figure 8, a brake band 32, similar to the band 13, isadapted to contact with the inner periphery of the drum 31, but in thisinstance, the brake band moves with the frame 30. To effect thismovement with the frame, the brake band 32 is supported at one side by abrace 33, which is connected at one end to the brake band and at theother end to the frame 30, preferably near the margin of the board. Atits opposite side the brake band is supported upon a bracket 34, alsocarried by the frame 30. (Figures 'l and '8.)

Rotation of the frame 30 and thebrake band 32 with respect to' the drum31 is normally prevented by the tension of a coil spring 35 which isanchored at one end to the frame 30 and has its free end hooked to anarm 36 which is pivoted in the bracket 34 and is adapted to rotate anelliptical cam 37 similar to the cam 19. Under the tension of the spring35, the cam 37 is normally rotated to press the free ends of the brakeband 32 apart and thus expand the brake hand against the inner peripheryof the drum 31 looking the brake band and the drum by this frictionalengagement. When it is desired to rotate the frame and brake band withrespect to the drum and thus adjust the angular relation of the drawingboard to the strut 11, a bell crank lever may be manipulated forinstance by hand. The lever 33 is pivoted on the frame 30, as at 38a,and is hingedly connected to one end of the link 39, which has its otherend hingedly connected to the arm 36. By pulling the handle 40 of thelever 38 toward the board 2, the cam 37 is rotated sufiiciently againstthe force of the spring 35, and in a reverse direction, to release thepressure of the cam on the brake band 32,

which permits the brake band and the frame 30 to turn. The handle 40desirably connects both of the levers 38, thus extending substantiallyacross the board to be readily accessible. Relatively light coil springs41, hooked across the segments of the brake band 32, supplement theresiliency of the band to effect its contraction away from the drum 31to the extent permitted by the cam 37.

A screw bolt 42 permits'of adjusting the tension of the spring 35.

A pencil trough 43 (Figure 2) may be arranged to depend from the lowermargin of the board 2, and a foot rest 44 desirably projects from thedesk 1 and is rigidly positioned below the board 2.

A stop 45 on the drum 31 desirably limits the downward movement of thestrut 11, by engaging the link 10.

So constructed and arranged, the board may be adjusted to a suitableheight for standing position or for sitting position at the height of anordinary chair. and at any desired angle of inclination. The mechanismis very nearly automatic and is simple to operate. No time consumingadjustments need to be made, and the hand and foot adjustments may bemade simultaneously and with very little effort. Furthermore, themechanism is kept clear of the top of the desk, permitting use of thedesk as a reference desk, since the drawing board is spaced therefrom atall times.

Obviously the inve'ntion is not limited to the specific details ofconstruction described above for illustration. Furthermore, it is notindispensible that all the features of the invention be used conjointly,as they may be advantageously employed in various combinations andsub-combinations.

Having described one embodiment of my invention, I claim:

1. In a device of the class described, the combination with a base, oflinks pivotally connected thereto, a counterbalancing spring connectedwith one of the links, a strut connecting one end of the links andmaintaining them in parallel relation, said strut being adapted to movedownwardly against the action of the counterbalancing spring, frictionclutch mechanism associated with one of the links and the base andadapted to adjust the angular relation of the links to the base at will,a pedal for controlling said clutch mechanism, a drawing boardor thelike, a frame rigidly attached to the drawing board and pivoted to thestrut, friction clutch mechanism associated with said strut and saidframe and adapted to adjust the angular relation of the board to thestrut, and a hand lever for controlling said latter clutch mechanism.

2. In a device of the class described, the combination with a base, of adrawing board or the like pivotally connected thereto, spring controlledfriction clutch mechanism adapted to adjust the angular relation of theboard to the base at will, and a relatively heavy springcounterbalancing said board when the clutch mechanism is released, saidspring operating upon a relatively long lever arm.

3. In a device of the class described, the combination with a base, of alink pivotally connected to the base, resilient friction clutchmechanism associated with said link and said base for adjusting theangular relation of the link to base, a drawing board or the likepivotally connected to said link, friction clutch mechanism foradjusting the angular relation of the board to link, and spring meansfor counterbalancing the weight of said board and link when the firstmentioned clutch mechanism is released including a spring connected witha relatively long lever arm integral with and oppositely directed fromsaid link.

4. In a device of the class described, the combination with a base, oflinks pivotally connected thereto, a strut connecting one end of thelinks and maintaining them in parallel relation, a drum rigidlyconnected with one of the links, friction clutch mechanism associatedwith said drum for adjusting the angular relation of the link to thebase, a spring normally maintaining said clutch mechanism in operativerelation with said drum, a lever pivoted to said base and adapted torelease said clutch mechanism against the force of the spring, anextension of said drum on the opposite side of said pivot point from thestrut, a counterbalancing spring connected to the base and to saidextension whereby the strut is adapted to move downwardly against theforce of the counterbalancing spring, a drum integral with the upper endof the strut, a drawing board or the like, a frame rigidly attached tothe drawing board and pivoted concentrically with said drum, frictionclutch mechanism associated with said bracket and said drum foradjusting the angular relation of the board to the strut, a springconnected to said frame and adapted to normally maintain said latterclutch mechanism in operative relation with said latter drum, and alever for releasing said latter clutch mechanism.

5. In a device of the class described, the combination with a desk, of adrawing board and mechanism connected to the rear of said desk forsupporting the drawing board in pivotal connection therewith, said boardbeing arranged to face away from the front of said desk and to be spacedfrom said desk top, whereby the drawing board and desk may be usedsimultaneously counterbalancing means for said board and mechanism and acompartment within the desk for housing said counterbalancing means.

6. In a device of the class described, the combination with a desk; of adrawing board; mechanism connected to the rear of said desk forsupporting the drawing board in pivotal connection therewith; aplurality of brake drums associated with said mechanism; a plurality ofspring actuated counterbalancing means for said board and mechanism; andcompartments at each end of counterbalancing means.

GEO. E. FROELICH.

